Head Gasket Going?

[JamesDaniel80]

Hi,

I bit of advice if you don't mind please.

I've just got my MK1b back on the road after about four years. I've driven it around 300 miles in the last few months but whilst out for a drive, I noticed that the coolant temperature gauge was nearly in the red.

I managed to let it cool down and when I got it back home, I found that I have been losing coolant.

There are no visible leaks that I can see and having checked the coolant and the oil, I can't see any signs of coolant in the oil or vice versa.

However...the exhaust is chucking out a lot of white smoke and having started it up this morning and let the engine warm up to optimum temperature, white smoke was still coming out of the exhaust and it looked like water was coming out too.

The only other thing I know that needs doing is my exhaust needs replacing as it's a bit holey now but I don't think that would be the cause of the smoke (and certainly wouldn't account for the coolant loss)

So...I'm thinking it's probably the beginnings of the head gasket failing, but would anyone with more experience of these engines have any other ideas?

Thanks!

James

[elbon50]

White smoke can be a symptom of ethelene glycol (antifreeze) being burnt James

So yes it seems likely that your head gasket is on the way out

Do you have access to a compression tester ?

[Charged]

I wouldn't panic quite yet, if it's been sat for a while the exhaust may be just burning off moisture..

Find the coolant leak, stop it, refill, bleed and see how you get on

[SuperRedMR2]

I had air in the system once which caused my needle to go into the red zone.

However when I rebuilt my engine I did find my head was ever so slightly bowed.

[BIGBOBO]

I can confirm that air in the system can make your car belch out white smoke.

I swapped in a 4AGZE that had been sitting for years and it wouldn't stop smoking. At first I thought it was all the moisture inside the block and exhaust but even after hours of idling it wouldn't stop.

The engine bleed screw (on top of the gearbox) was actually leaking slowly, letting air in every time and messing up sensors.

[PW@Woodsport]

Do you have access to a compression tester ?

What good will that do?

Compression tests do not highlight HG failures on Mr2s.

[elbon50]

Do you have access to a compression tester ?

What good will that do?

Compression tests do not highlight HG failures on Mr2s.

That's surprising

[cabbydave1]

Do you have access to a compression tester ?

What good will that do?

Compression tests do not highlight HG failures on Mr2s.

That's surprising

It would if you used it as a leak tester but that be a little to tech for the common mad Paul

[JamesDaniel80]

Thanks for all the replies.

Firstly, I don't have a compression tester so no good there.

It sailed through an MOT only a few months ago and the emissions were obviously fine.

I had it running for a good half an hour this morning and admittedly it was a bit on the cold side and it has been sat in the garage for a couple of weeks but there was no sign of the white smoke letting up. I suppose I could just take it for a bit of a drive and see whether the white smoke stops...if it doesn't, I know there's something coming out of the exhaust that shouldn't be there.

What's the best way of checking for a coolant leak. I was going for the 'checking the garage floor for puddles' approach, which didn't happen.

Over the last 300 or so miles it had lost about 1 litre of water which I would have thought would have an effect on what the oil looks like but the oil looks pretty good.

It's obviously going somewhere!

[elbon50]

Another thing you could try James

Cooling system topped up, engine running but not too hot, "rad" cap off

Increase revs a few times

Do you see bubbles in the coolant ?



Yes, keep taking it out for local runs & monitoring the smoke & coolant level

[JamesDaniel80]

I'll give that a go tomorrow.

Yesterday, when I topped up the coolant I started the engine before I put the radiator cap on. As soon as it started, some smoke/steam came from the coolant! I was starting it from cold so it wouldn't have been hot enough to produce steam. I thought that was odd.

There were a few bubbles but presumably that was air being pushed to the top when the water pump started turning.

That brings me to my next question...a head gasket change isn't really a job for a weekend mechanic such as myself is it?

[mk1 dal]

hi. its no good just topping the system up it must be bled to remove any air in the system . link http://myweb.tiscali.co.uk/jimilawson/V ... oling.html . bled the car and check for leaks , the obvious places to look are , rad , the heater matrix pipes ( under the front bulk head ) the 2 main pipes of the rad where they meet the main coolant pipes ( clips rust out ) check the header tank isn't filling with water and over flowing when driving ( pressure cap letting water past due to build up in pressure because of either air in system due to leak or air put in from hd breach ) i think if you bleed it properly it should be fine .

[laze]

Replacing the head gasket isn't a difficult job. Daunting if you haven't done it before, but not difficult. The real scary part is what you might uncover once you remove the head...

[Peter Gidden]

Replacing the head gasket isn't a difficult job. Daunting if you haven't done it before, but not difficult. The real scary part is what you might uncover once you remove the head...

Yep. Mk1 blocks are prone to surface corrossion and need surface grinding before rebuilding.

It's the corrossion that causes the overheating issue.

[JamesDaniel80]

Thank you but I completely replaced the coolant when I got the car back on the road and I know I bled it properly...hence I'm confident that it was full and free of air locks.

I've checked the heater matrix pipes and there's no signs of a leak there.

The filler cap is brand new too so I would hope that it hasn't failed already.

I'll have a look at the radiator tomorrow and see whether there's anything there that points to a leak but I can't help but think that the excess white smoke isn't significant.

Just in case, is there an online step-by-step guide for amateurs like me for a head gasket replacement? I've got the Haynes manual but sometimes that talks a completely different language to me!!

[mk1 dal]

ok mate your not a novice then when it comes to servicing your car which is now a cause for concern . i would check water isn't getting past the bleed screw on the engine ( will show coolant in the clear pipe and fill header tank until it over flows , i have had this problem before when changing coolant and the bottom o ring fails . new engine bled screw is 18 pounds from TOYOTA and has been redesigned for easy removal ) then see if any plugs are cleaner on the tips than they should be . if you use the Haynes manual it is wrong on the tightening down torque and another 90 degrees should be applied for the correct tightening . As peter has said if its has gone its more than likely the block not the head causing the Hg fail .

[pk_090]

Do you have access to a compression tester ?

What good will that do?

Compression tests do not highlight HG failures on Mr2s.

Sorry Paul but mine did. Quite significantly.

[JamesDaniel80]

Thank you. I'll check the bleed screw on the engine and see whether that reveals anything (fingers crossed).

And I don't have a compression tester but I can probably get hold of one easily enough. What symptoms would I be looking for? A simple lack of compression in one of the cylinders?

[PW@Woodsport]

Do you have access to a compression tester ?

What good will that do?

Compression tests do not highlight HG failures on Mr2s.

Sorry Paul but mine did. Quite significantly.

It will show a full blown indesputable failure, because it actually drops the compression in the blown cylinder/s.... however it is useless for detecting the normal "fine break" that Mk1s usually suffer from, which will not show up on a compression test.

You can find a 5%-10% compression variation between cylinders on a perfectly healthy engine, this is why compression tests are not 100% trustworthy.

My own routine diagnoses HG failures, even extremely minor breaches, every single time.

[JamesDaniel80]

Well this is what I'm dealing with...

https://www.dropbox.com/s/ir606gewgglki ... .35.22.jpg

This was just at idle...after 20 minutes ticking over followed by a 20 minute drive.

I quite literally disappear in a puff of smoke whenever I drive anywhere!